Barbara Walker Crossing: Safe Passage
The new bridge carrying the Wildwood Trail across West Burnside Street was lifted into place and secured over the weekend.
The 180-foot-long steel Barbara Walker Crossing was built in a workshop at Supreme Steel in Parkrose, cut into three pieces, and trucked to the site just east of where Northwest Barnes Road meets Burnside over five days last week. Burnside was closed for 48 hours while the pieces were lifted into place on pilings and welded back together.
Named for a parks activist, the Barbara Walker footbridge will make it possible to use the Wildwood Trail between Forest Park and Washington Park without crossing Burnside at street level.
The $3.2-million project is a coming together of multiple stakeholders and changing circumstances over time. The will of a core group of park activists kept the project going over almost three decades.
Randy Gragg, director of the Portland Parks Foundation, which raises money for Portland Parks & Recreation, has said the project unites two things Portlanders love: bridges and trails.
The bridge will connect "two great civic urban traditions to make an experience hikers, runners and drivers can love together," Gragg said. "Designing a work of public infrastructure is hard under the best of circumstances."
But from his first advocacy efforts that got the crossing off the ground, all the way through a very complicated public-private partnership, Ed Carpenter, the footbridge's designer, held on to his vision for a span that would be a fitting and visually exciting addition to the Wildwood Trail."
The bridge is striking for its green spikes, which vaguely resemble ferns or evergreen needles. But other parts of the bridge will change over time.
"What people don't yet get to see is that, over the winter, the crossing will gain a deeper level of beauty and fit into the surrounding nature as the unpainted steel seals itself with an earthy reddish-brown rust," Gragg said.
Shane Bliss, project manager at R&H Construction, said it was an extremely complicated installation. This was due to two things: "A tight worksite with heavy traffic that doesn't always obey the posted reduced speed limits around the construction site. Also, working with large bridge sections that are not only in a 'V' shape, but also on a 150-degree radius, requires extensive preplanning in order to erect each section safely."
The three sections, south to north, weighed 10 tons, 5.5 tons and 8 tons, respectively. Welding them together on the side of the road as traffic whizzed by took great care. Each weld is cataloged and tested.
"All shop welders and field welders are required to be AWS (American Welding Society) certified. Each welder has to perform testing on all welds called for by the structural engineer and pass all testing to become certified for each weld type," Bliss said.
"Test results are then submitted to the engineer of record for review and approval per the project specifications."
Surprisingly, cutting it up did not affect the bridge's strength. The field team used "erection aids" or collars and sleeves to make sure the main pieces were put back together solidly.
The maker, Supreme Steel, says the bridge is designed to handle 50 tons, with a maximum load of 74 tons. Since it is a pedestrian and bike bridge, it is unlikely ever to be put under that much stress.
But one person who lives in a nearby neighborhood is concerned about public safety. They pointed out that the Pittock bus stop, used regularly by tourists, does not provide direct access to the bridge. People who plan to use the bus to access the bridge may need to cross Burnside Street on foot at Barnes Road and walk about a quarter of a mile to access the bridge.
"The flashing yellow light at Barnes and Burnside is already an extremely dangerous intersection," they said, wishing to remain anonymous. "Cars will be moving faster than ever, thinking there are no pedestrians. I am hopeful the city will consider putting in a crosswalk or a stoplight at the Barnes-Burnside intersection to ensure public safety."
Several neighbors have a collection of crash photos at this intersection, but said calls to the Oregon Department of Transportation and the Portland Bureau of Transportation have resulted in frustration.
The artist as activist
Designer Carpenter's work can be seen all over the world — particularly in airports and public plazas. His large steel sculptures often resemble woven baskets or collections of straws tumbling through the air.
For the Wildwood Trail bridge, as it was first known, Carpenter set out to design a slender, graceful, almost transparent bridge. Along the way, he saw how extending some elements of the sides of the bridge might make them resemble sword ferns or vine maples, familiar from the trail.
But his goal was mostly structural. He worked with KPFF Consulting Engineers in Portland, and once they said the bridge could stand on one piling instead of two, the bridge became interesting in its asymmetry.
Carpenter said he thought the installation had gone very well, given how constricted the site was.
At this late stage in the project, he has been acting as a design consultant.
"I'm like the guardian of the aesthetics of the bridge. I'm making the difference between it being something that sings and something that just mumbles," he said. "But, really, I have no role now other than to stay out of the way."
Carpenter explained that the other stakeholders were also guardians of the project. KPFF, the engineers, have overseen the structural integrity of the bridge and following the specs. PBOT has made sure the permit processes were followed, and R&H Construction carried out the installation. Shiels Obletz Johnsen, a project management consultancy, is the coordinator of everyone. The Portland Parks Foundation is the client, and they are handing the bridge over to the Parks Bureau.
The final work being done this week includes attaching the railing ends and changing the Wildwood Trail to stop access to the roadway. Instead, the trail connects at either end of the bridge.
Carpenter readily admitted the structural design — a trichord truss — is "not particularly innovative." It's seen all the time on sign bridges across the freeway.
"It's been very exciting because of the complexity of the collaboration with all the different parties," Carpenter said, "and in my hometown, which is rare. I have a history with the trail as a runner, a real intimate relationship with the Wildwood. This is the only bridge I have designed where I was the design instigator."
Andrew Wheeler was the one who asked him to "have a crack at it," decades ago. Carpenter's process was to ask what all the stakeholders wanted.
Their response: a safe, continuous, delicate, iconic bridge that fits the site aesthetic, which could be constructed off-site, installed with minimal disruption, and prove cost-effective.
Carpenter designed several versions of the bridge, whittling them down to the current one. After that, the Portland Parks Foundation adopted it as a capital project, which meant people could donate to it (tax-free) as a nonprofit.
"They have the connections, clout, infrastructure and staffing to pull this off, and I became less involved," Carpenter said.
For him, the main thing is, "Portland gets a wonderful new bridge that solves a huge problem. It's just the way that it came about is unusual. I would not have had the knowledge or fortitude to carry it out had I not already had 40 years of experience in public art and be connected in Portland to people who could provide the resources."
Barbara Walker Crossing grand opening
What: Bridge Opening Celebration
When: 8:30 a.m.-noon Sunday, Oct. 27
Details: The event will feature a tribal blessing, plus a special "ribbon-tying" ceremony (at 9:30 a.m.) choreographed by world-renowned theatrical set designer Michael Curry and performed by dance troupe BodyVox.
There will be a fun run presented by Foot Traffic, all-you-can-eat pancakes, beverages, and a first crossing.
West Burnside between Northwest Hermosa and Barnes roads will be closed during the festivities.
What: Barbara Walker Crossing
Where: Wildwood Trail/West Burnside Street
Client: City of Portland
Dimensions: 180 feet by 12 feet by 8 feet
Materials: Welded painted steel and CorTen steel structure, fiberglass deck grating, stone paving at north landing
Design: Ed Carpenter 2012
Engineering: KPFF Consulting Engineers, Portland
Renderings: Curtis Pittman
Project administration: Arleen Daugherty
Reporter, The Business Tribune
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